SYNOPSIS

DESCRIPTION

The g_read_data() function reads length bytes of data from the provider
attached to consumer cp, starting at offset offset. The buffer returned
from g_read_data() is allocated with g_malloc(), so it should be freed by
the caller with g_free() after use. If the operation fails, an error
value will be stored in the error argument if it is not NULL.
The g_write_data() function writes length bytes of data from the buffer
pointed to by ptr to the provider attached to consumer cp, starting at
offset offset.

RESTRICTIONS/CONDITIONS

The length argument should be a multiple of the provider's sectorsize and
less than or equal to DFLTPHYS (DFLTPHYS is defined in <sys/param.h>).
The topology lock must not be held.

RETURNVALUES

The g_read_data() function returns a pointer to a data buffer or NULL if
an error occurred. In that case an error value is stored in the error
argument unless it is NULL.
The g_write_data() function returns 0 if successful; otherwise an error
code is returned.

ERRORS

Possible errors:
[EIO] An I/O error occurred while reading from or writing to
the consumer.